Diffracted moire fringes as analysis and alignment tools for multilayer fabrication in soft lithography

We studied the first-order diffracted moire fringes of transparent multilayered structures comprised of irregularly deformed periodic patterns. By a comparison study of the diffracted moire fringe pattern and detailed microscopy of the structure, we show that the diffracted moire fringe can be used as a nondestructive tool to analyze the alignment of multilayered structures. We demonstrate the alignment method for the case of layer-by-layer microstructures using soft lithography. The alignment method yields high contrast of fringes even when the materials being aligned have very weak contrasts. The imaging method of diffracted moire fringes is a versatile visual tool for the microfabrication of transparent deformable microstructures in layer-by-layer fashion. (c) 2005 American Institute of Physics.